Definition from Wiktionary, the free dictionary
Alternative forms 
- louvre (mainly UK)
- (UK) enPR: lo͞oʹvə, IPA: /ˈluːvə/, X-SAMPA: /"lu:v@/
- (US) enPR: lo͞oʹvər, IPA: /ˈluːvɚ/, X-SAMPA: /"lu:v@`/
louver (plural louvers)
- A slatted opening in a wall, door or window.
- Any of a series of narrow openings framed at their longer edges with slanting, overlapping fins or slats, adjustable for admitting light and air while shutting out rain.
- A fin or slat framing such an opening.
- A ventilating turret or lantern, as on the roof of a medieval building.
- Any of a system of slits, as in the hood of an automobile, for ventilation.
Derived terms 
a slatted opening in a wall, door or window
a series of narrow openings, framed with slanting adjustable slats
a fin or slat in such an opening
a ventilating turret or lantern
a system of slits for ventilation